The Selandian is a stage in the

Paleocene The Paleocene, ( ) or Palaeocene, is a geological epoch that lasted from about 66 to 56 million years ago (mya). It is the first epoch of the Paleogene Period in the modern Cenozoic Era. The name is a combination of the Ancient Greek ''pala ...

. It spans the time between . It is preceded by the

Danian The Danian is the oldest age or lowest stage of the Paleocene Epoch or Series, of the Paleogene Period or System, and of the Cenozoic Era or Erathem. The beginning of the Danian (and the end of the preceding Maastrichtian) is at the Cretac ...

and followed by the

Thanetian The Thanetian is, in the ICS Geologic timescale, the latest age or uppermost stratigraphic stage of the Paleocene Epoch or Series. It spans the time between . The Thanetian is preceded by the Selandian Age and followed by the Ypresian Age ( ...

. Sometimes the Paleocene is subdivided in subepochs, in which the Selandian forms the "middle Paleocene".

Stratigraphic definition

The Selandian was introduced in scientific literature by Danish geologist Alfred Rosenkrantz in 1924. It is named after the Danish island of

Zealand Zealand ( da, Sjælland ) at 7,031 km2 is the largest and most populous island in Denmark proper (thus excluding Greenland and Disko Island, which are larger in size). Zealand had a population of 2,319,705 on 1 January 2020. It is the 1 ...

( Danish: ''Sjælland'') given its prevalence there.Selandien

Den Store Danske Encyklopædi ''Den Store Danske Encyklopædi'' (''The Great Danish Encyclopedia'') is the most comprehensive contemporary Danish language encyclopedia. The 20 volumes of the encyclopedia were published successively between 1994 and 2001; a one-volume suppleme ...

The base of the Selandian is close to the boundary between

biozone In biostratigraphy, biostratigraphic units or biozones are intervals of geological strata that are defined on the basis of their characteristic fossil taxa, as opposed to a lithostratigraphic unit which is defined by the lithological properties ...

s NP4 and NP5. It is slightly after the first appearances of many new species of the calcareous

nanoplankton Plankton are the diverse collection of organisms found in water (or air) that are unable to propel themselves against a current (or wind). The individual organisms constituting plankton are called plankters. In the ocean, they provide a cruc ...

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

''Fasciculithus'' (''F. ulii'', ''F. billii'', ''F. janii'', ''F. involutus'', ''F. tympaniformis'' and ''F. pileatus'') and close to the first appearance of calcareous nanoplankton species ''Neochiastozygus perfectus''. At the original type location in Denmark the base of the Selandian is an

unconformity An unconformity is a buried erosional or non-depositional surface separating two rock masses or strata of different ages, indicating that sediment deposition was not continuous. In general, the older layer was exposed to erosion for an interval ...

. The official GSSP was established in the

Zumaia , leader_title = Mayor , leader_name = Iñaki Ostolaza Esnal ( EH Bildu) , area_code = +34 (Spain) + 943 (Gipuzkoa) , website zumaia.eus Zumaia (, es, link=no, Zumaya) is a small town i ...

section (43° 18'N, 2° 16'W) at the beach of Itzurun in the Basque Country, northern

Spain , image_flag = Bandera de España.svg , image_coat = Escudo de España (mazonado).svg , national_motto = '' Plus ultra'' (Latin)(English: "Further Beyond") , national_anthem = (English: "Royal March") , ...

GSSP Golden spike Itzurun, Zumaia, Basque Country (02)

The top of the Selandian (the base of the Thanetian) is laid at the base of magnetic chronozone C26n. The Selandian Stage overlaps with the lower part of the

Tiffanian The Tiffanian North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), typically set from 60,200,000 to 56,800,000 years BP lasting . It is usually c ...

North American Land Mammal Age The North American land mammal ages (NALMA) establishes a geologic timescale for North American fauna beginning during the Late Cretaceous and continuing through to the present. These periods are referred to as ages or intervals (or stages when ...

, the

Peligran The Peligran ( es, Peligrense) age is a period of geologic time (62.5–59.0 Ma) within the Paleocene epoch of the Paleogene, used more specifically with South American land mammal ages (SALMA). It follows the Tiupampan and precedes the Riochican ...

Tiupampan The Tiupampan ( es, Tiupampense) age is a period of geologic time (64.5–62.5 Ma) within the Paleocene epoch of the Paleogene used more specifically with South American land mammal ages (SALMA). It is the oldest SALMA age and precedes the Peligr ...

and lower

Itaboraian The Itaboraian ( pt, Itaboraiense) age is a period within the Early Eocene geologic time (53.0–50.0 Ma) epoch of the Paleogene, used more specifically with South American land mammal ages (SALMA). It follows the Riochican and precedes the Cas ...

South American Land Mammal Ages and part of the Nongshanian

Asian Land Mammal Age The Asian land mammal ages, acronym ALMA, establish a geologic timescale for prehistoric Asian fauna beginning 58.7 Mya during the Paleogene and continuing through to the Miocene ( Aquitanian) (23.03 Ma). These periods are referred to as ages, sta ...

. It is coeval with the lower part of the Wangerripian Stage from the

Australia Australia, officially the Commonwealth of Australia, is a sovereign country comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands. With an area of , Australia is the largest country by ...

n regional timescale. The start of the Selandian represents a sharp depositional change in the

North Sea The North Sea lies between Great Britain, Norway, Denmark, Germany, the Netherlands and Belgium. An epeiric sea on the European continental shelf, it connects to the Atlantic Ocean through the English Channel in the south and the Norwegian ...

Basin, where there is a shift to siliciclastic deposition due to the uplift and erosion of the

Scotland Scotland (, ) is a country that is part of the United Kingdom. Covering the northern third of the island of Great Britain, mainland Scotland has a border with England to the southeast and is otherwise surrounded by the Atlantic Ocean to ...

Shetland Shetland, also called the Shetland Islands and formerly Zetland, is a subarctic archipelago in Scotland lying between Orkney, the Faroe Islands and Norway. It is the northernmost region of the United Kingdom. The islands lie about to the n ...

area after nearly 40 million years of calcium carbonate deposition. This change occurs at the same time as the onset of a

foreland basin A foreland basin is a structural basin that develops adjacent and parallel to a mountain belt. Foreland basins form because the immense mass created by crustal thickening associated with the evolution of a mountain belt causes the lithosphere ...

formation in

Spitsbergen Spitsbergen (; formerly known as West Spitsbergen; Norwegian: ''Vest Spitsbergen'' or ''Vestspitsbergen'' , also sometimes spelled Spitzbergen) is the largest and the only permanently populated island of the Svalbard archipelago in northern Nor ...

due to compression between

Greenland Greenland ( kl, Kalaallit Nunaat, ; da, Grønland, ) is an island country in North America that is part of the Kingdom of Denmark. It is located between the Arctic and Atlantic oceans, east of the Canadian Arctic Archipelago. Greenland ...

and

Svalbard Svalbard ( , ), also known as Spitsbergen, or Spitzbergen, is a Norwegian archipelago in the Arctic Ocean. North of mainland Europe, it is about midway between the northern coast of Norway and the North Pole. The islands of the group rang ...

, suggesting a common tectonic cause that altered the relative motions of the

Greenland Plate The Greenland Plate is a supposed tectonic plate bounded to the west by Nares Strait, a probable transform fault; on the southwest by the Ungava transform underlying Davis Strait; on the southeast by the Mid-Atlantic Ridge; and the northeast by t ...

and the

Eurasian Plate The Eurasian Plate is a tectonic plate that includes most of the continent of Eurasia (a landmass consisting of the traditional continents of Europe and Asia), with the notable exceptions of the Indian subcontinent, the Arabian subcontinent an ...

. This plate reorganisation event is also manifest as a change in

seafloor spreading Seafloor spreading or Seafloor spread is a process that occurs at mid-ocean ridges, where new oceanic crust is formed through volcanic activity and then gradually moves away from the ridge. History of study Earlier theories by Alfred Wegener a ...

direction in the

Labrador Sea The Labrador Sea (French: ''mer du Labrador'', Danish: ''Labradorhavet'') is an arm of the North Atlantic Ocean between the Labrador Peninsula and Greenland. The sea is flanked by continental shelves to the southwest, northwest, and northeast. It ...

around this time.

Fauna and Flora

The fauna of the Selandian consisted of giant snakes (''

Titanoboa ''Titanoboa'' (; ) is an extinct genus of very large snakes that lived in what is now La Guajira in northeastern Colombia. They could grow up to , perhaps even long and reach a body mass of . This snake lived during the Middle to Late Paleo ...

''), crocodiles, champsosaurs, Gastornithiformes,

owls Owls are birds from the Order (biology), order Strigiformes (), which includes over 200 species of mostly Solitary animal, solitary and Nocturnal animal, nocturnal birds of prey typified by an upright stance, a large, broad head, binocular vi ...

; and a few archaic forms of mammals, such as Mesonychids, Pantodonts, primate relatives Plesiadapids, and Multiberculates. The flora was composed of cacti, ferns, and palm trees.

References

External links

GeoWhen Database - SelandianPaleogene timescale
at the website of the subcommission for stratigraphic information of the ICS
Stratigraphic chart of the Paleogene
at the website of Norges Network of offshore records of geology and stratigraphy {{coord, 43, 18, 02, N, 2, 15, 34, W, region:EH_type:landmark_source:kolossus-euwiki, display=title Paleocene geochronology Geological ages

Stratigraphic definition

Fauna and Flora

References

Further reading

External links